Role of Plasma Electron Vortex Formation at Laser Interaction with Foil for Ion Acceleration

2010 ◽  
Author(s):  
V. I. Maslov ◽  
A. M. Egorov ◽  
I. N. Onishchenko ◽  
Giuseppe Bertin ◽  
Franca De Luca ◽  
...  
2008 ◽  
Vol 26 (1) ◽  
pp. 69-82 ◽  
Author(s):  
A.Ya. Faenov ◽  
A.I. Magunov ◽  
T.A. Pikuz ◽  
I.Yu. Skobelev ◽  
D. Giulietti ◽  
...  

AbstractWe used X-ray spectroscopy as a diagnostic tool for investigating the properties of laser-cluster interactions at the stage in which non-adiabatic cluster expansion takes place and a quasi-homogeneous plasma is produced. The experiment was carried out with a 10 TW, 65 fs Ti:Sa laser focused on CO2 cluster jets. The effect of different laser-pulse contrast ratios and cluster concentrations was investigated. The X-ray emission associated to the Rydberg transitions allowed us to retrieve, through the density and temperature of the emitting plasma, the time after the beginning of the interaction at which the emission occurred. The comparison of this value with the estimated time for the “homogeneous” plasma formation shows that the degree of adiabaticity depends on both the cluster concentration and the pulse contrast. Interferometric measurements support the X-ray data concerning the plasma electron density.


2005 ◽  
Vol 86 (26) ◽  
pp. 264103 ◽  
Author(s):  
Joel P. McDonald ◽  
Arthur A. McClelland ◽  
Yoosuf N. Picard ◽  
Steven M. Yalisove

Laser Physics ◽  
2006 ◽  
Vol 16 (2) ◽  
pp. 376-378
Author(s):  
W. V. Pogosov ◽  
K. Machida

Author(s):  
Dario Collia ◽  
Luigino Zovatto ◽  
Giovanni Tonti ◽  
Gianni Pedrizzetti

The right and left sides of the human heart operate with a common timing and pump the same amount of blood. Therefore, the right ventricle (RV) presents a function that is comparable to the left ventricle (LV) in terms of flow generation; nevertheless, the RV operates against a much lower arterial pressure (afterload) and requires a lower muscular strength. This study compares the fluid dynamics of the normal right and left ventricles to better understand the role of the RV streamlined geometry and provide some physics-based ground for the construction of clinical indicators for the right side. The analysis is performed by image-based direct numerical simulation, using the immersed boundary technique including the simplified models of tricuspid and mitral valves. Results demonstrated that the vortex formation process during early diastole is similar in the two ventricles, then the RV vorticity rapidly dissipates in the subvalvular region while the LV sustains a weak circulatory pattern at the center of the chamber. Afterwards, during the systolic contraction, the RV geometry allows an efficient transfer of mechanical work to the propelled blood; differently from the LV, this work is non-negligible in the global energetic balance. The varying behavior of the RV, from reservoir to conduct, during the different phases of the heartbeat is briefly discussed in conjunction to the development of possible dysfunctions.


2007 ◽  
Vol 581 ◽  
pp. 453-468 ◽  
Author(s):  
MATTHEW J. RINGUETTE ◽  
MICHELE MILANO ◽  
MORTEZA GHARIB

We investigate experimentally the force generated by the unsteady vortex formation of low-aspect-ratio normal flat plates with one end free. The objective of this study is to determine the role of the free end, or tip, vortex. Understanding this simple case provides insight into flapping-wing propulsion, which involves the unsteady motion of low-aspect-ratio appendages. As a simple model of a propulsive half-stroke, we consider a rectangular normal flat plate undergoing a translating start-up motion in a towing tank. Digital particle image velocimetry is used to measure multiple perpendicular sections of the flow velocity and vorticity, in order to correlate vortex circulation with the measured plate force. The three-dimensional wake structure is captured using flow visualization. We show that the tip vortex produces a significant maximum in the plate force. Suppressing its formation results in a force minimum. Comparing plates of aspect ratio six and two, the flow is similar in terms of absolute distance from the tip, but evolves faster for aspect ratio two. The plate drag coefficient increases with decreasing aspect ratio.


1995 ◽  
Vol 7 (9) ◽  
pp. 2288-2290 ◽  
Author(s):  
C. Chyu ◽  
J.‐C. Lin ◽  
J. Sheridan ◽  
D. Rockwell

2021 ◽  
pp. 2000181
Author(s):  
Debin Zou ◽  
Mingyang Yu ◽  
Xiangrui Jiang ◽  
Na Zhao ◽  
Tongpu Yu ◽  
...  

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